时间同步协议在远程视频监控系统中的实现

为了使远程视频监控系统能够同步到一个标准时间上,采用了NTP网络对时协议,NTP协议以UTC时间作为时间源,进行层层对准,其毫秒级精度足以满足视频监控系统的需求。作者针对导航台站远程视频监控系统,设计了本文的时间同步方案,该方案利用现有网络资源,最大程度减少了成本的投入,最后作者进行了实验测试,证明了该方案的可行性,在实际使用中,该方案可以有效的满足导航设备的远程视频监控系统对于时间同步的需求。     

基于NTP协议的计算机时间同步及监控系统设计

文章提出一种基于NTP(网络时间协议)的局域网内计算机时间同步和监控方法,自主开发了NTP客户端软件WSNTP以及监控软件WSNTP monitor,设计了通信协议及监控帧格式,提出了客户端监控组网方案。实际应用表明,本系统具有同步精度高、监控内容丰富、监控方式灵活多样、功能完善、操作简单等特点。应用本系统可实现局域网内计算机时间同步及远程监控功能。     

中央广播电视总台4K超高清播出系统时钟监测方案浅析

中央广播电视总台4K超高清播出系统的时钟系统主要是以NTP网络时间协议来进行授时.为了保障系统中时钟的准确性,监控系统对各级设备都进行了时间监测.本文介绍了该套系统中时钟系统的基本架构,各级设备的时钟报警情况以及监控系统利用NTP协议来监测时钟源时间的比对算法.     

校园无线视频监控系统的设计与应用

为解决校园内及周边视频监控点布置分散等原因造成的无法实现远程视频监控问题,针对3G无线网络的特点,描述了基于3G标准的无线视频监控系统关键技术的研究与实现方法。在数据传输中利用RTP协议中时间戳,解决音视频同步的问题,对监控系统的客户端与服务器端进行了设计。实际应用表明,该系统设计合理,可靠性好,能对校园内外目标实现有效监控。     

基于Internet网络的远程视频监控传输安全性研究

基于Internet网络的视频监控系统已越来越受到人们的关注,如何保证远程视频监控系统的安全性是需要深入研究的课题。给出一种采用H.323通信协议实现安全的远程视频监控的方法。该方法在H.323协议的基础上,增加了系统在呼叫控制过程中被监控端参与的安全认证,加强了远程视频监控业务的安全性。而且,由于采用标准的H.323多媒体协议,使相应的视频监控系统不仅具有完善的呼叫控制和媒体控制过程,而且具有较好的互通性和可扩展性。     

利用GPS时钟及NTP实现广电网络时钟同步

随着广电系统双向网络改造的完成,视频类业务的多样化运营,广电系统网络中的相关设备对于时钟同步信息的需求越来越高。本文为了解决广电系统网络设备类型多样,设备分层架构组网的特点,基于广电系统接收GPS时钟作为精确时钟源的特点,使用NTP协议完成全网部署时钟源同步的方案。     

NTP协议在Y.1731中的应用研究

随着信息技术和网络技术的发展,人们对时间同步的精度要求越来越高。网络时间协议(NTP,Network Time Protocol)是一种基于UDP的时间同步协议。介绍了NTP协议的基本原理,Y.1731单端DM原理。通过NTP协议在Y.1731报文中的应用研究和实践,使传统的网络时间同步精度能达到毫秒级别。实验数据表明,文中所设计的网络时钟同步系统比传统的时钟同步具有更高的时钟同步精度。     

以太网的时钟同步技术

随着分散控制的发展和系统范围的扩大,通过网络联系的分散控制节点之间的时间同步技术变得越来越重要。同步技术相当于一个网络系统的心脏,它为该系统中的每个模块传送正确的时钟信号。分析了目前以太网应用中的3类时钟同步协议：IEEE1588、NTP（网络时间协议）及SNTP（简单网络时间协议）,具体说明了IEEE1588、NTP及SNTP的基本原理,并对3类协议进行了简要的对比分析。     

分布式姿态基准系统中时间同步技术的实现

首先分析比较了两种重要的时间同步技术——网络时间协议(NTP)和直接连接时间传输技术，然后提出了一个基于Windows2000的高精度的时间同步方案，并给出了该方案的软硬件的实现，且已成功地应用于分布式姿态基准系统。     

基于电力线通信和流媒体视频监控系统设计

设计了一种基于电力线载波通信和流媒体技术的视频监控系统实现方案。系统采用ARM11处理器S3C6410作为主控器,利用内置视频硬件编解码模块对摄像头采集到的视频数据进行编码压缩,通过实时传输协议RTP和传输层的UDP协议进行网络层的封包,再经电力载波调制解调器封装成PLC帧格式后由电力网络传输,最后在PC机上接收视频数据并显示实时视频。测试结果表明,该方案成本低廉,基本能够满足视频监控项目的需求,在普通的电力环境下效果理想。     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.